An unmanned aerial vehicle is an unmanned aircraft manipulated by means of radio remote control equipment and a self-contained program control device. The application of the unmanned aerial vehicle has expanded to a plurality of civil fields. The unmanned aerial vehicle represented by agricultural applications usually adopts a form of multiple rotor wings, and is an aircraft having a plurality of propellers, and a plurality of aircraft arms for arrangement of the propellers which are in a crossed form. As the plurality of propellers are arranged around the aircraft and provide approximately equal lift forces, the total lift force is equivalent to acting on an intersection point of the aircraft arms, i.e. a geometric center of a plane where an airframe is. Thus, other weight-bearing components of the unmanned aerial vehicle are arranged upon and/or below the geometric center so as to make an acting point of the total gravity of the aircraft close to the geometric center of the plane of the airframe as much as possible, thus keeping a balance with the total lift force.